This disclosure is generally directed to toner processes, and more specifically, emulsion aggregation and coalescence processes, as well as toner compositions formed by such processes and development processes using such toners for use with electrophotographic copying or printing apparatus.
Toner blends containing crystalline or semi-crystalline polyester resins with an amorphous resin have recently been shown to provide very desirable ultra low melt fusing, which is important for both high-speed printing and lower fuser power consumption. These types of toners containing crystalline polyesters have been demonstrated suitable for both emulsion aggregation (EA) toners, and in conventional jetted toners. Combinations of amorphous and crystalline polyesters may provide toners with relatively low-melting point characteristics (sometimes referred to as low-melt, ultra low melt, or ULM), which allows for more energy-efficient and faster printing.
Emulsion aggregation/coalescing processes for the preparation of toners are illustrated in a number of patents, such as U.S. Pat. Nos. 5,290,654, 5,278,020, 5,308,734, 5,344,738, 6,593,049, 6,743,559, 6,756,176, 6,830,860, 7,029,817, and 7,329,476, and U.S. Patent Application Publication Nos. 2006/0216626, 2008/0107990, 2008/0236446, and 2009/0047593. The disclosures of each of the foregoing patents are hereby incorporated by reference in their entirety.
In the EA process, aggregating agents, including those possessing aluminum, are sometimes used to aggregate the toner particles. However, residual aluminum ions in a toner may reduce the gloss of an image produced with such a toner. Thus, chelating agents may be used to remove the aluminum ions after the aggregation step to achieve target gloss levels in prints made with these toners. When using the same amount of aggregating agent, increasing the amount of chelating agent may remove more aluminum ions from the toner, thus further increasing the toner gloss.
However, one issue which may arise in these processes is batch to batch variability of the aluminum ions in the final toner particles which, in some cases, can be out of target specifications for a toner. Improved toners and methods for their production thus remain desirable.